1. Field of the Invention
The present invention relates to semiconductor device manufacturing procedures and, in particular, to manufacturing procedures that optimize semiconductor substrate processing equipment performance.
2. Description of the Related Art
Semiconductor device manufacturing often involves the processing of a semiconductor substrate (e.g. a silicon wafer) through a series of steps, including the implantation of dopant atoms into the substrate, the formation of insulating and conducting layers on the substrate and the subsequent patterning of the layers via lithography and etching techniques. Cost effective semiconductor device manufacturing requires that both the design of the equipment used to process the semiconductor substrate in each step and the manufacturing procedures employed to operate such equipment be optimized in terms of equipment throughput, non-generation of equipment particulates and process uniformity.
For certain types of equipment and, in particular , single wafer Chemical Vapor Deposition (CVD) chambers and single wafer plasma etch chambers, process uniformity (such as wafer-to-wafer etch rate uniformity and layer deposition rate uniformity) can be degraded if the equipment is not in a proper preconditioned state upon the onset of processing. Furthermore, excessive particulate generation . from sources within the equipment can result in malformed patterned layers and inoperable devices, and may lead to other undesirable consequences. While intrusive equipment maintenance procedures can be employed to decrease particle levels therein, these procedures consume valuable equipment time that would otherwise be available for semiconductor substrate processing and, therefore, reduce equipment throughput.
Cycled purge processes designed to reduce particle/contaminant levels in Low Pressure Chemical Vapor Deposition (LPCVD) furnace equipment are known in the art. See U.S. Pat. 5,728,602 to Bellows et al., which is hereby fully incorporated by reference. Conventional cycled purge processes are, however, targeted solely at reducing particle/contaminant levels and do not provide for maintaining the equipment chamber and associated hardware in a proper preconditioned state.
There is, therefore., still a need in the field for a process that maintains a semiconductor substrate layer deposition equipment chamber in a proper preconditioned state, reduces particle levels, and improves equipment throughput by prolonging the time between intrusive maintenance procedures.